4In medium bowl, beat filling ingredients with electric mixer until light and fluffy. For each whoopie pie, spread about 2 teaspoons of the filling on bottom of 1 cooled cookie. Top with second cookie, bottom side down; gently press together. Store tightly covered in refrigerator. Sprinkle with additional powdered sugar just before serving.

Expert Tips

Use the leftover marshmallow creme to make easy s’mores—just spread on a graham cracker, top with a piece of chocolate candy bar (softened slightly in the microwave) and a second graham cracker.